Splicing tape, splicing method and assembly comprising the splicing tape

ABSTRACT

Splicing tape for splicing a leading edge portion of a roll of sheet material to a further sheet comprising a carrier layer having on a first major surface a first adhesive layer and on a second major surface opposite to the first major surface in the order given a non-tacky polymer layer and a second adhesive layer. The splicing tape being capable of delamination between the carrier layer and the non-tacky polymer layer when preparing the splice.

METHOD OF SPLICING FIELD OF THE INVENTION

The present invention relates to a method of preparing a flying orpermanent splice between a first and second sheet material, to thesplices thus obtained and to splicing tapes suitable for splicing aleading edge portion of the outer turn of a roll of sheet material toanother sheet material.

BACKGROUND OF THE INVENTION

Splicing tapes can be used for preparing a joint between two sheetmaterials such as, for example, between the leading edge portion of theouter turn of a roll of sheet material and another sheet material. Thesplicing operation can be performed in a static or a dynamic mode.

In the static mode the first and second sheet material may be positionedfirst in the desired configuration relative to each other, and one ormore splicing tapes are then applied in order to join the two sheetstogether. It is also possible to apply the splicing tape or tapes to oneof the sheet materials first. Then the second sheet material isprovided, positioned in the desired configuration and the two sheetmaterials are joined. Splices which are obtained in a static mode ofpreparation are often referred to as permanent splices. Depending on theconfiguration of the two sheet materials relative to each other, it canbe differentiated between butt splices, overlap splices and staggeredoverlap splices, respectively. The different configurations are shownand explained in WO 95/29,115.

It is often desirable, however, to prepare splices in a dynamic mode.This allows, for example, in the printing industry, to join the leadingedge of the new roll of paper sheet material to the trailing edge of theold, depleting roll of paper sheet material without requiringinterruption of the continuous production process. Splices which areobtained in a dynamic mode of operation, are usually referred to asflying splices. A conventional way of making a flying splice tape usesdestructible nose tabs as is described in WO 95/29,115. In a first stepthe new roll is appropriately prepared or “dressed” for splicing, as isshown in FIG. 1a which was taken from WO 95/29,115. The leading edge 35of the outermost turn 32 of the new roll of sheet material 30 is cut,for example, in the form of a W or V or in another appropriate shape. Adouble-sided adhesive tape 24 is applied to the leading edge portion ofthe outermost turn 32 which is releasably adhered to thenext-to-the-outer turn 31 by the nose tabs 23. The new roll of sheetmaterial 30 is then accelerated to the same speed as the running websheet of the previous, depleting roll. The running web sheet is thenpressed against the new roll 30 and pasted to the double-sided adhesivetape 24 on the outermost turn 32 of the new roll 30. The previous rollis typically cut off from the running web sheet. The nose tab is thensubjected to the tractive force exerted by the running web sheet. Thenose tab breaks thereby releasing the temporary joint between the outerturn 32 and the next-to-the-outer turn 31 of the new roll of sheetmaterial 30.

An alternative configuration for applying a flying splice which is usedin the state-of-the-art is shown in FIG. 1b which was adapted from WO95/29,115.

A nose tab which is suitable for preparing a flying splice is describedin GB 2,294,235. As can be seen from this reference, the nose tabcomprises two adhesive layers which are adhered to the under-surface ofthe leading edge portion of the outer turn and the upper-surface of thenext-to-outer turn, respectively. The nose tab furthermore comprises twothin paper layers which are attached to two adhesive layers and embracea silicon lacquer layer. The new roll of sheet material is thenfurthermore prepared by applying a double-sided adhesive tape to theleading edge of the outer turn to provide a configuration similar tothat of FIGS. 1a or 1 b, respectively. When making the splice, the paperweb sheet from the depleting roll which is advanced, is adhered to theexposed part of the adhesive layer and the exposed adhesive layer of thedouble-sided tape, thereby causing the lacquer layer to cohesively splitinto two parts. On breaking the nose tab of GB 2,294,235 leaves behindtwo non-tacky surfaces.

Both permanent and flying splices should provide a flexible, strongconnection between the two sheet materials or webs and should maintainsubstantially all of the properties of the sheet material; for example,if the sheet material is paper which can be printed or coated, thesplice is preferably thin, flexible, printable, coatable and alsorepulpable. When using configurations like those of FIGS. 1a and 1 b forpreparing a flying splice, it is important that air cannot enter beneaththe leading edge 35 of the outer turn 32 which would result in the rollunwinding itself at very high speeds thus interrupting the continuousproduction. In order to prevent air entering beneath the leading edge 35of the outer turn 32, small destructible adhesive tabs 26 are sometimesapplied not only at the noses of the leading edge 35 but, for example,also along the diagonal edges of the leading edge 35 in FIG. 1a or overthe lateral edges of the leading portion 34 of the outer turn 32 to thesides of the roll 30 (see FIG. 1b). Configurations like those of FIGS.1a and 1 b are time consuming to apply and require the application ofdouble-sided adhesive tapes and destructible nose tabs.

Another flying splice multi-layer film or multi-layer adhesive,respectively, is disclosed in German utility model DE 92 01 286.8 U1comprising perforated and non-perforated embodiments. The non-perforatedembodiments are required to exhibit a low adhesive force so that the newpaper web is easily released after splicing. It is furthermore requiredthat the open adhesive spots which are exposed upon splicing arespecifically modified so that they do not stick to rolls, cylinders,rods and spindles. It is disclosed that these requirements can befulfilled by specifically selecting pressure-sensitive adhesives,permanent adhesives and surfaces, which stick to each other but not toother surfaces such as rolls, spindles and cylinders.

It was therefore an object of the present invention to provide asplicing tape and a method of preparing a flying splice which does notrequire using a destructible nose tab in combination with a double-sidedadhesive tape. It was another object of the present invention to providea splicing tape which allows to reliably and easily prepare a new rollof sheet material 30 for making a splice and, in particular, for makinga flying splice which on delamination leaves behind two non-tackysurfaces. It was another object of the present invention to provide asplicing tape with the peeling force required to delaminate the splicingtape being adjustable within wide limits. Other objects of the presentinvention can be taken from the following description of the invention.

BRIEF DESCRIPTION OF THE INVENTION

The present invention refers to a method of splicing a leading edgeportion of the outer turn of a roll of sheet material to a further sheetcomprising the steps of

(i) providing a splicing tape comprising a carrier layer having on afirst major surface a first adhesive layer and on a second major surfaceopposite to the first major surface in the order given anadhesion-controlling layer, a non-tacky polymer layer and a secondadhesive layer, the splicing tape being capable of delamination betweenthe carrier layer and the adhesion-controlling layer or between thenon-tacky polymer layer and the adhesion-controlling layer,respectively, when preparing the splice,

(ii) positioning said tape on and adhering it by means of one of theadhesive layers, to the portion of the upper surface of thenext-to-the-outer turn of the roll of sheet material facing the leadingedge portion of the outer turn so that the other adhesive layer of thesplice tape can be fully or partly adhered to the under-surface of theleading edge portion of the outer turn,

(ii) adhering the other adhesive layer of the splice tape fully orpartly to the under-surface of the leading edge portion of the outerturn of the roll of sheet material,

(iv) optionally providing an adhesive tape having a first adhesivesurface and a second adhesive surface, and adhering one of the adhesivesurfaces to the upper surface of the leading edge portion of the outerturn of the roll of sheet material,

(v) adhering the further sheet to the optionally partially exposedsurface of the other adhesive surface of the splicing tape and/or to theexposed surface of the other adhesive layer of said optional adhesivetape, and

(vi) separating the further sheet and the outer turn of the roll splicedto it, from the next-to-the-outer turn of the roll thereby effectingdelamination between the carrier layer and the non-tacky polymer layerof the splicing tape.

The present invention furthermore refers to a splicing tape suitable forsplicing a leading edge portion of the outer turn of a roll of sheetmaterial to another sheet material, said splicing tape comprising acarrier layer having on a first major surface a first adhesive layer andon a second major surface opposite to the first major surface in theorder given an adhesion-controlling layer, a non-tacky polymer layer anda second adhesive layer, the splicing tape being capable of delaminationbetween the carrier layer and the adhesion-controlling layer or betweenthe non-tacky polymer layer and the adhesion-controlling layer,respectively, when preparing the splice.

The present invention furthermore refers to a flying or permanent splicebetween a first and a second sheet material which is obtainable by usingsplicing tape according to the present invention.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1a and b schematically show two prior art configurations for“dressing” a new roll of sheet material 30 for making a flying splice(prior art).

FIG. 2 shows an embodiment of a splicing tape 10 comprising in the orderof sequence a first release liner 11, a first adhesive layer 12, acarrier layer 13, a non-tacky polymer layer 14, a second adhesive layer15 and a second release liner 16.

FIG. 3 shows an embodiment of the splicing tape 10 according to thepresent invention additionally comprising an adhesion-controlling layer17 between the carrier layer 13 and the non-tacky polymer layer 14.

FIG. 4 shows a new roll of sheet material 30 which comprises a splicingtape 10 between the outer turn 32 and the next-to-the-outer turn 31 ofthe new roll 30.

FIG. 5a is an enlarged view of the part of FIG. 4 comprising thesplicing tape 10, the leading edge 35 of the outer turn 32 of the newroll, the corresponding portions of the next few inner turns of the newroll and portion 42 of the running web sheet 41.

FIG. 5b is a perspective view of the new roll of sheet material 30 whichis “dressed” for the preparation of a flying splice and comprises asplicing tape 10 applied between the outer turn 32 and thenext-to-the-outer turn 31 of the new roll of sheet material 30 along theleading edge 35 of the outer turn 32.

FIG. 6 shows the preparation of a flying splice between portion 42 ofthe running web sheet 41 of the depleting roll 40 and the outer turn 32of the new roll of sheet material 30, using the configuration shown inFIG. 5a and pressing portion 42 against the exposed surface 12 A of thefirst adhesive layer 12 of the splicing tape 10.

FIG. 7 shows another configuration of a new roll of sheet material whichis “dressed” for the preparation of a flying splice, said configurationcomprising a splicing tape 10 and another adhesive tape 39 which isattached to the upper-surface of the leading edge portion 34 of theouter turn 32 of the new roll 30 and comprises an additional adhesivesurface protected by a release liner 36.

FIG. 8 shows the preparation of a flying splice between portion 42 ofthe running web sheet 41 of the depleting roll 40 and the outer turn 32of the new roll of sheet material 30, using the configuration shown inFIG. 7 and pressing portion 42 against the exposed surface of adhesivetape 39.

DETAILED DESCRIPTION OF THE INVENTION

In connection with the present invention, the term of “non-tacky polymerlayer 14” as used above and below, denotes a polymer layer that is nottacky at ambient conditions of humidity and temperature.

The term “delamination” as used above and below refers to an adhesivedestruction mode of the splicing tape 10 whereby the splicing tape 10separates between two adjacent layers so as to leave exposed thesurfaces of the adjacent layers which had been in contact with eachother previously.

The term “splitting” as used above and below refers to a cohesivedestruction mode of the splicing tape 10 whereby the splicing tape 10breaks through one of its layers so as to leave exposed two innersurfaces of such layer.

A first embodiment of a splicing tape 10 is shown in FIG. 2. Thesplicing tape comprises a carrier layer 13 having on a first majorsurface a first adhesive layer 12 and on a second major surface oppositeto the first major surface in the order given a non-tacky polymer layer14 and a second adhesive layer 15. A preferred embodiment of a splicingtape 10 according to the present invention which is shown in FIG. 3,differs from the embodiment of FIG. 2 in that it additionally comprisesan adhesion-controlling layer 17 between the non-tacky polymer layer 14and the carrier layer 13.

The adhesive layers 12 and 15 of the splicing tape 10 of the presentinvention can be the same or different but preferably are the same. Theadhesive layers 12 and 15 may include any known adhesive thatpermanently and strongly adheres to the outer turn 32 andnext-to-the-outer turn 31 of the new roll 30 and to the further sheetmaterial the leading edge portion 34 of the outer turn 32 is to bespliced to. Examples include pressure sensitive adhesives, heatactivated adhesives, thermosetting type adhesives and remoistenableadhesives. Particularly preferred adhesives include pressure sensitiveadhesives which may be hot-melt adhesives, essentially solvent orwater-free adhesives or solvent- or water-based dispersions orsolutions. Specific pressure sensitive adhesives include acrylate-basedpressure sensitive adhesives, styrene-isoprene block copolymers, acrylicester-vinyl acetate copolymers, ethylene-vinyl acetate copolymers,plasticized vinyl acetate homopolymers and rubber-latex resin emulsionsystems. In the practice of preferred embodiments of the invention, theadhesive composition comprises an acrylate-based pressure sensitiveadhesive. Acrylate-based pressure sensitive adhesives useful inpracticing the invention comprise polymers of one or more monomers of(meth)acrylic acids and optionally other copolymerizable monomerscontaining functional groups in addition to an ethylenically unsaturatedgroup. The acrylate-based pressure sensitive adhesive may compriseconventional additives such as, for examples, fillers, anti-oxidants,flame-retardants, pigments, plasticizers or polymer additives. Byvarying the nature and amount of the monomers and the nature and amountof the additives, the cohesive properties of the resulting adhesive canbe changed as is known in the art.

Examples of acrylate-based pressure sensitive adhesives which aresuitable in the practice of the invention are described in Satas,“Acrylic Adhesives,” Handbook of Pressure-Sensitive Adhesive Technology,2nd ed., pp. 394-456 (D. Satas, ed.), Van Nostrand Reinhold, New York(1989).

A particularly suitable acrylate based pressure sensitive adhesiveincludes copolymers of an acrylic or methacrylic acid and an alkylacrylate or methacrylate wherein the alkyl group has at least 4 carbonatoms, typically 4 to 14 carbon atoms. Examples of such alkyl acrylatesor methacrylates include n-butyl, n-pentyl, n-hexyl, cyclohexyl,isoheptyl, n-nonyl, n-decyl, isohexyl, isobornyl, 2-ethyloctyl,isooctyl, and 2-ethylhexyl acrylates and methacrylates. Preferred alkylacrylates include isooctyl acrylate, 2-ethylhexyl acrylate,n-butylacrylate and cyclohexyl acrylate. A particularly preferred alkylacrylate is isooctyl acrylate. Particularly preferred alkylmethacrylates include butyl methacrylate, cyclohexyl methacrylate, andisobornyl methacrylate.

In accordance with a highly preferred embodiment in connection with thisinvention, the adhesive layers 12 and 15 comprise a repulpable adhesive.A preferred repulpable adhesive for use in this invention has a ratingof not more than 3 in the European repulpability test described in U.S.Pat. No. 5,380,779. Examples of repulpable adhesives for use in theinvention include the repulpable adhesives disclosed in U.S. Pat. No.5,380,779, U.S. Pat. No. 4,413,080, U.S. Pat. No. 4,569,960, U.S. Pat.No. 4,482,675, U.S. Pat. No. 4,388,432, U.S. Pat. No. 5,102,733 and U.S.Pat. No. 5,125,995. The thickness of the adhesive layers 12 or 15 can bevaried widely but is typically independent of each other between 10 μmand 200 μm and preferably between 10 μm and 50 μm.

The carrier layer 13 can be, for example, of any material commonly usedfor backings of tapes and includes paper layers as well as plasticfilms. Suitable carrier layers include polyethylene films, polypropylenefilms, polyester films, polyethylene or polypropylene coated papers,Kraft papers and non-woven materials. In case paper is used at carrierlayer 13, it is preferred to use smooth papers of low porosity. Papercarrier layers 13 are preferred because of their repulpability. Thethickness of carrier layer 13 is typically between 30 μm and 250 μm andpreferably between 40 μm and 100 μm.

Examples of polymers for use in the non-tacky polymer layer 14 of thesplicing tape 10 of this invention include polyvinyl chlorides,polyvinylidene chlorides, polyvinyl alcohols such as Mowiol™ 4/88available from Clariant, polyvinylacetates, polyvinyl pyrrolidones andcopolymers of vinylchloride and vinylacetate such as UCAR™ vinyl VYESand UCAR™ vinyl VMCA both commercially available from Union Carbide. Thenon-tacky polymer layer 14 may contain additives in addition to thepolymer. For example, the non-tacky polymer layer 14 may additionallycontain wetting agents, defoamers, plasticizers and fungicides. Aparticularly preferred non-tacky polymer layer comprises a repulpablepolymer such as polyvinylalcohol. A non-tacky polymer layer 14containing a polyvinylalcohol preferably also contains a plasticizer orcombination of plasticizers. Particularly preferred plasticizers for usein a polyvinyl alcohol based non-tacky polymer layer 14 include acombination of a polyol such as diethylene glycol and a hydroxy-modifiedrubber such as Kraton™ L 1803 available from Shell. The thickness of thenon-tacky polymer layer 14 is preferably between 1 μm and 40 μm and morepreferably between 10 μm and 15 μm.

The splicing tape 10 according to the present invention preferablycomprises one or two release liners 11, 16 which are attached to theexposed surfaces of adhesive layers 12, 15 for storage and protection.If the splicing tape is provided in roll form only one release linerhaving release properties on both surfaces, may be required between theadhesive layers 12, 15. The splicing tape according to the presentinvention can also be provided, however, in the form of sheets and isthen typically protected by two release liners 11, 16.

The release liners 11 and 16 can be selected from a number of known andavailable papers or films having a release material coated onto one sideof the web or on both sides in case of an adhesive tape in the form of aroll. The base paper of the release liner may be selected from krafts,super-calendered krafts, clay coated krafts, glassines, parchments, andother papers and films which have a suitable undercoating for releasecoating hold-out. The release coating may be any of the known materialsused for their release properties for adhesives. Preferred types aresilicones and modified silicones, the modification including bothcopolymerization of silicones with other nonrelease chemical agents orby adding nonsilicone materials to the silicone coating solution priorto application to the release base paper. Other release agents such aspolyethylene, fluorocarbons, the Werner-type chromium complexes, andpolyvinyl octadecyl carbamate may also be used. The choice of releasecoating is dependent on the tack, adhesion level, and chemical nature ofthe adhesive layer 12 or 15. The release liners 11 and 16 are chosensuch that when they are removed from the adhesive tape no prematuredelamination takes place between the carrier layer 13 and the non-tackypolymer layer 14.

FIG. 4 illustrates a method according to the present invention using thesplicing tape 10 for making a flying splice between the trailing end ofa depleting roll of sheet material 40 which is being advanced, and a newroll of sheet material 30. FIG. 5a shows enlarged and in more detail theleading edge portion 34 of the outer turn 32 of new roll 30, thesplicing tape 10 according to FIG. 2 comprising no adhesion-controllinglayer 17, the next-to-outer turn 31 of new roll 30 and a few followinginner turns of the new roll 30, the running web sheet 41 of thedepleting roll 40 and the portion 42 of the running web sheet 41 whichis to be connected to the exposed part 12A of adhesive layer 12. Thesplicing tape 10 is adhered to portion 38 of the upper-surface of thenext-to-the-outer turn 31 of the new roll 30 in a way so that the undersurface of the leading edge portion 34 next to the leading edge 35 canbe adhered to the part 12B of the adhesive layer 12 leaving the part 12Aof the adhesive layer 12 exposed. The splicing tape 10 can be applied invarious configurations. In a preferred embodiment the splicing tape isapplied along essentially all of the leading edge 35 of the new roll 30in order to effectively suppress lifting of the leading edge bypreventing air from entering between the outer turn 32 and thenext-to-outer turn 31 at the leading edge 35. A specific embodiment isshown in FIG. 5b where the leading edge 35 of the outer turn 32 of thenew roll 30 is essentially parallel to the longitudinal symmetry axis ofthe new roll 30. The splicing tape 10 according to the invention can,however, also be applied as a nose tab, typically together with anadditional double-sided adhesive tape which is attached at or close tothe leading edge 35 of the outer turn 32 as is shown in FIG. 1a.

In order to make the splice, the new roll 30 is rotated about itslongitudinal symmetry axis and brought to a peripheral speedcommensurate with the linear speed of the running web sheet 41 of thedepleting roll 40. In an appropriate moment, when the depleting roll 40is close to exhaustion and the leading edge 35 of the new roll 30 is inan appropriate rotational position relative to the portion 42 of therunning web sheet 41 of the depleting roll 40, the running web 41 ismoved, for example, by means of a roller towards the leading edgeportion 34 of the outer turn 32 of the new roll 30 so that theunder-surface of portion 42 of the running web 41 is adhered to theexposed surface 12A of the first adhesive layer 12 of the splicing tape10. When traveling out of the area of contact where the running websheet 41 is adhered to the splicing tape 10, the running web sheet 41exerts a peeling force onto the splicing tape 10 as is shown in FIG. 6.This effects the splicing tape to delaminate between the carrier layer13 and the non-tacky polymer layer 14, leaving behind the non-tackysurface of polymer layer 14 on the upper surface of thenext-to-the-outer turn 31 and the non-tacky surface of the carrier layer13 at the splice between the leading edge portion 34 of the outer turnof the new roll 30 and the portion 42 of the running web sheet 41 of thedepleting roll 40. The running web sheet 41 is preferably cutessentially simultaneously to or shortly after making the splice byusing the cutting device 50 as is indicated in FIG. 6.

The embodiment of the splicing tape 10 according to the presentinvention which includes an adhesion-controlling layer 17 between thecarrier layer 13 and the non-tacky polymer layer 14 as is shown in FIG.3 is preferred. The adhesion-controlling layer 17 is chosen so that theinterface between the adhesion-controlling layer 17 and the carrierlayer 13 or the non-tacky polymer layer 14, respectively, becomes thepredetermined breaking point of the splicing tape. The carrier layer 13,the non-tacky polymer layer 14 and the adhesion-controlling layer 17 arepreferably selected so that the adhesion-controlling layer 17 adheresmore strongly to the carrier layer 13 than to the non-tacky polymerlayer 14 so that the splicing tape 10 delaminates on peeling between theadhesion-controlling layer 17 and the non-tacky polymer layer 14.

The force f necessary to peel the adhesion-controlling layer 17 from thenon-tacky polymer layer 14 is measured as 90° peel adhesion as isdescribed in the test method section below. The force f preferably isbetween 5 and 40 g/cm, and more preferably between 10 and 25 g/cm.

The adhesion-controlling layer 17 can be chosen to either increase ordecrease the force necessary to cause delamination of the splicing tape10 having no adhesion-controlling layer 17. In case the carrier layer 13is of plastic, it may be desirable to increase the force necessary tocause delamination of the splicing tape 10 because in that case, thepeel force c may be so small that a splicing tape 10 comprising noadhesion-controlling layer 17, could delaminate during handling.Alternatively, the surface of the carrier layer 13 may be given a coronatreatment to increase the peel force c.

The adhesion-controlling layer 17 typically includes a release materialsuch as silicone or fluorine containing material. Particularly suitablematerials are silicone-containing materials. By varying the amount ofsilicone in the adhesion-controlling layer 17, the force required fordelaminating the splicing tape 10 between the adhesion-controlling layer17 and the non-tacky polymer layer 14 or the carrier layer 13,respectively, can be adjusted as desired. A particularly desirablerelease material for the adhesion-controlling layer 17 is an aqueousemulsion of silicone latex, available from Rhone-Poulenc as Silicolease®emulsion system, further containing a hydrophilic binder such ashydroxyethyl cellulose. Still further materials for use in theadhesion-controlling layer 17 include the release materials described inEP-A0618509. U.S. Pat. No. 5,202,190 and U.S. Pat. No. 5,032,460.According to a still further embodiment of the present invention, apolyurethane layer can be used as the adhesion-controlling layer 17. Thelatter offers the advantage that after delamination, the surface of thecarrier layer 13 containing the adhesion-controlling layer 17 will beprintable and writable.

The force required for delaminating the splicing tape 10 between theadhesion-controlling layer 17 and the non-tacky polymer layer 14 or thecarrier layer 13, respectively, may also be adjusted by providing apatterned adhesion-controlling layer 17. For example, a silicone releasematerial typically used to produce a release liner, may be applied byflexographic printing to the carrier layer 13 such that only about 50 to95%, more preferably about 80 to 95% of the carrier's surface is coveredby the release material. As a result, the peel force between theadhesion-controlling layer 17 and the non-tacky polymer layer 14 or thecarrier layer 13, respectively, will be low at places where the releasematerial covers the surface of the carrier layer 13 or the non-tackypolymer layer 14, respectively, and will be higher at places where suchsurfaces are not covered. Since the force necessary to causedelamination between the adhesion-controlling layer 17 and the carrierlayer 13 or the non-tacky polymer layer 14, respectively, is the averageof the force at a place where release material covers the carrier layer13 or the non-tacky polymer layer 14, respectively, and where it doesnot cover such layers, the delamination force can be adjusted by varyingthe amount of surface coverage by the release material ofadhesion-controlling layer 17.

The splicing tape of the present invention can be prepared in variousways. For example, in a first step the carrier layer 13 may be coated onits major surface with the adhesion-controlling layer 17. Such coatingmay be applied by well known coating techniques such as hopper orgravure coating followed by drying and/or curing. The second majorsurface of the carrier layer 13 may be optionally treated with a primerlayer, followed by coating the first pressure sensitive adhesive layer12 with subsequent curing and/or drying, and application of the releaseliner 11. Alternatively, the pressure sensitive adhesive layer 12 may belaminated to the second major surface of the carrier layer 13 as atransfer tape hearing a release liner 11 on its outer surface.

The non-tacky polymer layer 14 is then coated onto theadhesion-controlling layer 17. This may, for example, be accomplished byhopper coating or any other coating technique known in the art. Finally,the second adhesive layer 15 is coated or laminated to the non-tackypolymer layer 14, optionally followed by the application of a secondrelease liner 16 to the exposed surface of the second adhesive layer 15.The second release liner 16 may be omitted when winding up the splicingtape 10 in roll form. Splicing tapes suitable for slicing a leading edgeportion 34 of the outer turn 32 of a roll of sheet material 30 toanother sheet material, which comprise an adhesion-controlling layer 17are novel, and they are subject matter of the present invention.

The flying splice 10 according to the present invention is suitable formaking a flying splice as is described above and is schematically shownin FIGS. 5a and b and 6. Splices of this type are preferably obtained byusing splicing tapes 10 comprising an adhesion-controlling layer 17.

The splicing tape 10 according to the present invention can also be usedto make flying overlap splices as is shown in FIGS. 7 and 8. As can beseen from FIG. 7, subsequent to the application of the splicing tape 10,an adhesive tape 39 having two adhesive surfaces, is adhered with oneadhesive surface to the upper-surface of the leading edge portion 34 ofthe out turn 32 of the new roll of sheet material 30. The adhesive tape39 may consist of an adhesive layer which is preferably laminated to theupper-surface of the leading edge portion 34, for example, by means of arubber roller with the outer surface of the adhesive layer beingprotected with a release liner 36. Coating of an adhesive layer 39 ontothe upper-surface of the leading edge portion 34 of the outer turn 32 isalso possible but less preferred. Adhesive tapes consisting of a singleadhesive layer are often termed as transfer tapes. The adhesive tape 39may also be a double-sided adhesive tape comprising a carrier layer(often referred to as backing) bearing an adhesive layer on each of itstwo major surfaces. The doubled-sided adhesive tape is also preferablylaminated onto the upper-surface of the leading edge portion 34 of theouter turn 32 with the upper adhesive layer being protected by a releaseliner 36. The release liner 36 is then removed from the adhesive tape39, and the new roll of sheet material 30 is ready for the splice makingoperation.

The adhesive layer or layers, respectively, and, optionally, the carrierlayer of the adhesive tape 39 are preferably selected from the pool ofmaterials described above for use in the splicing tape 10 or,alternatively, are selected following the guidelines given above. Theadhesive layer or layers, respectively, preferably comprise pressuresensitive adhesive material with acrylate based pressure sensitivematerials being especially preferred. The carrier layer of the adhesivetape 39, if present, preferably is a polymer layer or paper. Theadhesive tape 39 preferably is repulpable. Furthermore, the adhesivetape 39 preferably is a transfer tape having a thickness of between30-200 μm and, more preferably, of between 40-150 μm, in order to reducethe thickness of the splice. If a double-sided adhesive tape 39 is used,the adhesive layers preferably have a thickness independently from eachother of between 30-150 μm and the carrier layer preferably is between30-200 μm.

The splice making operation for the flying overlap splice which ispreferably performed analogously to the method described above for theflying butt splice, and the splitting behavior of the splicing tape 10is shown in FIG. 8. Flying overlap splices are preferably obtained byusing splicing tapes 10 comprising an adhesion-controlling layer 17. Itis evident from the comparison of the flying butt splice of FIG. 6 withthe flying overlap splice of FIG. 8, that the flying overlap spliceexhibits a higher step at the change from the trailing end of the websheet 41 of the previous roll 40 to the leading edge portion 35 of thenew roll 30. This step may cause problems, for example, in—or in theworst case disrupt—a subsequent printing process. On the other hand, theflying overlap splice construction may be advantageous in case the newroll 30 and the depleting roll 40 comprise different sheet materials. Inthis case, the first adhesive layer 12 of the splicing tape and theexposed adhesive layer of adhesive tape 39, respectively, may beselected to provide excellent adhesion to the leading edge portion 32 ofthe outer turn of the new roll 30 and to the portion 42 of the runningweb sheet 41 of the depleting roll 40, respectively.

The splicing tape 10 of the present invention may also be used toprepare permanent splices. In this case, a first sheet material such as,for example, a new roll of sheet material 30 is prepared as shown inFIG. 5a or FIG. 7, respectively. The trailing end of the other sheetmaterial 41 is then attached to the new roll to provide a permanent buttsplice, a permanent overlap splice or a permanent staggered overlapsplice construction similar to those of WO 95/29,115. Additionalone-sided adhesive tapes 26 may optionally be additionally used as isshown in FIGS. 1A and 1B in order to further secure the splice. Splicingtapes 10 according to the present invention comprising anadhesion-controlling layer, are preferred.

The splicing tape 10 according to the present invention may also be usedto provide an assembly comprising a first surface and a second surface,the first surface being releasably adhered to the second surface, byadhering the first adhesive layer 12 of the flying splice tape 10 to thefirst surface and the second adhesive layer 15 to the second surface.

The splicing tape 10 according to the present invention may also be usedas nose tab or core starting tape. In the latter application, splicingtape 10 is first applied to the core of a roll by means of adhesivelayer 15. The sheet material is then adhered to the core by means ofadhesive layer 12 of the splicing tape 10 and wound around the core togive a roll of sheet material 30. Upon unwinding, the sheet material isproperly released from the core leaving behind two non-tacky surfaces.

The splicing tape 10 according to the present invention exhibits highlyadvantageous properties.

On delamination, the splicing tape 10 provides two non-tacky surfaces.If an adhesion-controlling layer 17 is present, the splicing tape 10provides on delamination the surface of the adhesion-controlling layer17 which typically is non-tacky together with the surface of thenon-tacky polymer layer 14 or the carrier layer 13, respectively,depending on the relative adhesion forces and the delamination scheme.Splices with non-tacky surfaces are preferred in that they do notadversely affect further processing of the spliced web sheet, forexample, in a printing machine.

Contrary to the nose tab described in GB 2,294,235, the splicing tapes10 of the present invention exhibit an adhesive delamination mode, i.e.the splicing tape delaminates between two layers instead of cohesivelybreaking through one layer. The adhesive force between the carrier layer13 and the non-tacky polymer layer 14 and, in particular, between theadhesion-controlling layer 17 and the carrier layer 13 or the non-tackypolymer layer 14, respectively, can be varied and optimized with respectto a specific application by selecting appropriate combinations ofmaterials for the respective layer and/or using an appropriatelypatterned adhesion-controlling layer 17. This high variability allowsthe splicing tape 10 of the present invention to be applied, forexample, in the construction of FIG. 5b in order to prepare a new rollof sheet material 30 for making a flying splice. This construction whichcan be easily applied by one operator only, reliably prevents air fromlifting the outer turn 32 of the new roll 30. Contrary to this, thecohesive strength of a layer can only be changed by changing thechemical composition of this layer. Controlling and varying thesplitting behavior of a splicing tape 10 having a cohesive failure modeis therefore more difficult, and GB 2,294,235 consequently onlydiscloses a nose tab. The cohesive strength of the silicon lacquer layerwhich is the predetermined cohesive breaking point of such nose tab, canonly be reduced by providing a strip pattern as is indicated in FIG. 1of GB 2,294,235.

Contrary to the flying splice tapes referred to in German utility modelDE 92 01 286.8 U1, the splicing tapes 10 of the present inventioncomprise an adhesion-controlling layer 17.

Test methods

1. Adhesion force a between the first adhesive layer 12 and carrierlayer 13

The adhesion force a is measured as 90° peel adhesion using a modifiedversion of PSTC Method PSTC-3 which is available from the PressureSensitive Tape Council of Glenview, Ill., U.S.A.

A polyester film (thickness 23 μm) having a free end, was laminated ontoadhesive layer 12 adhered to carrier layer 13 and a 2.54 cm wide stripof the resulting laminate was obtained. The carrier layer 13 of thisstrip was then bonded to a stainless steel plate using high tackdouble-sided adhesive tape number 411 available from Minnesota Miningand Manufacturing Company, St. Paul, Minn., U.S.A.

The adhesion force a is measured at room temperature by removing thefree end of the polyester film away from the stainless steel plate by90° at a rate of 300 mm/min using an Instron tensile tester.

2. Adhesion force b between the second adhesive layer 15 and thenon-tacky polymer layer 14

The adhesion force b is measured as 90° peel adhesion using a modifiedversion of PSTC Method PSTC-3 which is available from the PressureSensitive Tape Council of Glenview, Ill., U.S.A.

The non-tacky polymer layer 14 was coated onto a Silicote 6625 (57 g/m²)paper substrate available from Ahlstrom Paper Group, and dried. Adhesivelayer 15 was applied to the non-tacky polymer layer 14, and then apolyester film (thickness 23 μm) having a free end, was laminated ontoadhesive layer 15. A 2.54 cm wide strip of the resulting laminate wasthen bonded to a stainless steel plate using high tack double-sidedadhesive tape number 411 available from Minnesota Mining andManufacturing Company, St. Paul, Minn., U.S.A.

The adhesion force b is measured at room temperature by moving the freeend of the polyester film away from the stainless steel plate by 90° ata rate of 300 mm/min using an Instron tensile tester.

3. Adhesion force c between the non-tacky polymer layer 14 and thecarrier layer 13

The adhesion force c is measured as 90° peel adhesion using a modifiedversion of PSTC Method PSTC-3 which is available from the PressureSensitive Tape Council of Glenview, Ill., U.S.A.

A three-layer structure comprising in the order given the adhesive layer15 bonded to non-tacky polymer layer 14 which was attached to carrierlayer 13, was provided and a polyester film (thickness 23 μm) having afree end, was laminated onto adhesive layer 15. A 2.54 cm wide strip ofthe resulting laminate was then bonded to a stainless steel plate usinghigh tack double-sided adhesive tape number 411 available from MinnesotaMining and Manufacturing Company, St. Paul, Minn., U.S.A.

The adhesion force c is measured at room temperature by moving the freeend of the polyester film away from the stainless steel plate by 90° ata rate of 300 mm/min using an Instron tensile tester.

4. Adhesion force f between the adhesion-controlling layer 17 and thenon-tacky polymer layer 14

The adhesion force f is measured as 90° peel adhesion using a modifiedversion of PSTC Method PSTC-3 which is available from the PressureSensitive Tape Council of Glenview, Ill., U.S.A.

A three-layer structure comprising in the order given the carrier layer13, the adhesion-controlling layer 17 and the non-tacky polymer layer14, was laminated to one-sided adhesive tape no. 810 available fromMinnesota Mining and Manufacturing Company, St. Paul, Minn., U.S.A., thebacking of which having a free end. Then a 2.54 cm wide strip of theresulting laminate was obtained. The carrier layer 13 of this strip wasthen bonded to a stainless steel plate using high tack double-sidedadhesive tape number 411 available from Minnesota Mining andManufacturing Company, St. Paul, Minn., U.S.A.

The adhesion force f is measured at room temperature by moving the freeend of the polyester film away from the stainless steel plate by 90° ata rate of 300 mm/min using an Instron tensile tester.

EXAMPLE 1

a) The following coating solutions were prepared:

Coating solution for the adhesion-controlling layer 17 (coating solution1-A): 33 parts of polyvinylalcohol modified with 67 parts of octadecylisocyanate were dissolved in toluene in an amount of 6.7%.

Coating solution for the non-tacky polymer layer 14 (coating solution1-B): An aqueous solution containing the following components wasprepared:

Polyvinylalcohol (Mowiol ™ 4-88, available from Clariant) 94.5%Diethylene glycol 5.0% p-Hydroxymethylbenzoate 0.3%p-Hydroxypropylbenzoate 0.1% Surfynol ™ 336 (available from AirProducts) 0.1%

Coating solution for the adhesive layers (coating solution 1-C) 12 and15, respectively: A 40% solids solution in a 1:1 mixture of ethylacetate and methanol was prepared containing 100 parts of acryliccopolymer of butyl acrylate and acrylic acid (75/25), 75 parts of ahydrogenated rosin acid tackifier, 70 parts of mono-fenyl ether oftetraethylene glycol (or tetraphenyl glycol phenyl ether) as aplasticizer and 65 parts of N-methyldiethanolamine as a neutralizingagent.

b) Preparation of the splicing tape 10:

Silcote 6625 paper (57 g/m²) available from Ahlstrom Paper Group wasused as the carrier layer 13. Silcote 6625 is a smooth paper that hasbeen provided on one side (hereinafter A-side) with a barrier coatingcontaining a latex polymer, silicates and starch. The opposite side ofthe paper was uncoated (B-side).

The A-side of the paper was coated with coating solution 1-A using Meyerbar coating with a 35 μm wire and parallel bar speed. The coating wasdried and the obtained dry coating thickness was about 2-3 μm.

To this layer was then coated the coating solution 1-B using a nip feedcoater with a feed gap of 40 μm. The coating was dried at an elevatedtemperature and the obtained dry coating thickness was about 8-13 μm. Acoated paper sample A was thus obtained.

Separately, there was coated the coating solution 1-C to a siiconizedrelease liner using nip feed coating with a 100 μm gap. After drying, acoating thickness of about 35 μm was obtained.

The adhesive coated release liner thus obtained was laminated with theadhesive layer on the coated side (side A) of the coated paper sample A.At the opposite side of the paper sample (side B), an adhesive layer wasprovided by transferring the adhesive layer from the above preparedadhesive coated release liner to the paper. The resulting splicing tape10 was wound to a roll.

c) Preparation of a flying splice:

A 1.2 m wide roll of 72 g/m² weight paperstock was dressed for use asthe new roll 30. A strip of the splicing 10 tape obtained above in b),measuring 1.2 m in length (same as the width of the roll) and being 50mm wide was used to adhere the leading edge portion 35 of the outer turn32 to the next-to-outer turn 31 of the new roll 30 in the configurationshown in FIGS. 5a and 5 b. The tape was applied along the width of theentire leading edge 35 of the outer turn 32 (FIG. 5b) in such a position(FIG. 5a) so that the leading edge 35 was adhered to the next-to-outerturn 31 of the paper roll, but also so that portion 12A of the firstpressure-sensitive adhesive layer 12 of the splicing tape 10 was notcovered by the leading edge portion 34. Approximately 15 mm of the tapewidth was covered by the leading edge portion 34 and 35 mm was leftexposed and available to make the adhesive bond with the running websheet 41 of the old roll 40.

The new paper roll 30 bearing the above splicing tape 10 in theconfiguration just described was brought up to the traveling speed ofthe running web sheet 41 on conventional paper web handling equipment. Aflying splice was performed at 400 m/min as shown schematically in FIG.6. The splicing tape 10 clearly delaminated between theadhesion-controlling layer 17 and the non-tacky polymer layer 14, andthe flying butt splice obtained remained intact during the subsequentprocessing at 400 m/min.

d) Measurement of peel forces a and b

Peel forces a and b were measured as is described in the test methodsection above using the layers specified in Example 1. The followingvalues were obtained:

a=240 g/cm

b=160 g/cm

EXAMPLE 2

The splicing tape of Example 1 was employed in the manner shown in FIG.7. A piece of tape of the invention measuring 1.2 m×50 mm was adheredalong the entire leading edge 35 of the outer turn 32 of the new paperroll 30 in such a manner that both of the adhesive surfaces of the tapewere fully covered and used to bond the outer turn 32 to thenext-to-outer turn 31. No pressure-sensitive adhesive was exposed.

A separate length of double-coated pressure-sensitive adhesive tape 39(Tape number 415 from 3M Company, St. Paul, Minn., USA) having a lengthof 1.2 m and a width of 50 mm was adhered separately to the outersurface of the leading edge 35 of the outer turn 32 as shown in FIG. 7.The protective release liner 36 was removed from this tape, exposing theadhesive surface as shown in FIG. 8.

The new paper roll 30 dressed for making the splice, was brought up tothe traveling speed of the running web sheet 41 on conventional paperweb handling equipment. A flying splice was made at 400 m/min as shownschematically in FIG. 8. The splicing tape 10 clearly delaminatedbetween the adhesion-controlling layer 17 and the non-tacky polymerlayer 14, and the flying overlap splice obtained remained intact duringthe subsequent processing at 400 m/min.

EXAMPLES 3 to 7

a) Preparation of splicing tape:

A paper (ADERCOTE™ Gerfast 80 g/m² available from Ahlstrom Paper Group)coated on one side with a latex polymer (A-side) and uncoated on theother side (B-side) was provided. A silicon release composition as shownin Table 1 was then coated to the A-side of the paper using doctor bladecoating without a shim. A very thin adhesion-controlling layer 17 wasthus obtained. The coating solution 1-B of example 1 was coated onto theadhesion-controlling layer 17 at a dry thickness of 8-12 μm, followed byapplying the adhesive coating solution 1-C of example 1 at a drythickness of 38-45 μm. The adhesive layer was dried and protected with arelease liner. The adhesive coating solution 1-C was coated to theopposite side (B-side) of the paper at a dry thickness of 38-45 μm, andthis adhesive layer was also protected with a release liner.

TABLE 1 Example number Release composition 3 4 5 6 7 A700 40 40 40 40 4071822 0.64 0.8 0.96 1.12 1.28 71823 0.064 0.08 0.096 0.112 0.128 718060.0256 0.032 0.0384 0.0448 0.0512 Peel force f [g/cm] 25 22 20 20 17

Notes:

(1) Amounts of the components of the coating solution in grams.

(2) The components of the release coating were specifically:

A700 is a solution of a silicone latex in water (40% solids)(Silicolease™ A700 available from Rhône-Poulenc),

71822 is a solution of a silicone polymer in water (41.5% solids)(Silicolease™ 71822 available from Rhône-Poulenc),

71823 is a solution of a catalyst in water (40.9% solids) (Silicolease™71823 available from Rhône-Poulenc), and

71806 is a solution of crosslinker in water (57% solids) (Silicolease™71806 available from Rhône-Poulenc).

b) Measurement of peel force f

The peel force f was measured as is described in the test section aboveusing the layers as specified in Examples 3-7. The results aresummarized in table 1.

What is claimed is:
 1. Method of splicing a leading edge portion (34) ofthe outer turn (32) of a roll of sheet material (30) to a further sheetcomprising the steps of (i) providing a splicing tape (10) comprising acarrier layer (13) having on a first major surface a first adhesivelayer (12) and on a second major surface opposite to the first majorsurface in the order given an adhesion-controlling layer (17), anon-tacky polymer layer (14) and a second adhesive layer (15), thesplicing tape being capable of delamination between the carrier layer(13) and the adhesion-controlling layer (17) or between the non-tackypolymer layer (14) and the adhesion-controlling layer (17),respectively, when preparing the splice, (ii) positioning said tape onand adhering it by means of one of the adhesive layers (12), (15), tothe portion of the upper surface of the next-to-the-outer turn (31) ofthe roll of sheet material (30) facing the leading edge portion (34) ofthe outer turn (32) so that the other adhesive layer of the splice tape(10) can be fully or partly adhered to the under-surface of the leadingedge portion (34) of the outer turn (32), (iii) adhering the otheradhesive layer of the splice tape to the under-surface of the leadingedge portion (34) of the outer turn (32) of the roll of sheet material(30), (iv) optionally providing an adhesive tape (39) having a firstadhesive surface and a second adhesive surface, and adhering one of theadhesive surfaces, respectively, to the upper surface of the leadingedge portion (34) of the outer turn (32) of the roll of sheet material(30, (v) adhering the further sheet to the optionally partially exposedsurface of the other adhesive layer of the splicing tape (10) and/or tothe exposed surface of the other adhesive surface of said optionaladhesive tape (39), and (vi) separating the further sheet and the outerturn of the roll splice to it, from the next-to-the-outer turn of theroll thereby effecting delamination between the carrier layer (13) andthe non-tacky polymer layer (14) of the splicing tape (10).
 2. Methodaccording to claim 1 wherein the adhesion-controlling layer (17) and thenon-tacky polymer layer (14) are selected so that the splicing tape (10)is capable of delamination between such layers when preparing thesplice.
 3. Method according to claim 2 wherein the force f necessary topeel the non-tacky polymer layer (14) from the adhesion-controllinglayer (17) is between 5 and 40 g/cm.
 4. Method according to claim 1wherein the adhesion-controlling layer (17) of the splicing tape (10)comprises a polysiloxane or fluorinated polyurethane.
 5. Methodaccording to claim 1 wherein the non-tacky polymer layer (14) comprisesa polymer selected from the group consisting of polyvinyl alcohols,polyvinyl chlorides and copolymers of vinyl acetate and vinyl chloride.6. Method according to claim 1 wherein the carrier layer (13) comprisespaper.
 7. Assembly comprising a first and second sheet material splicedto each other, said assembly being obtainable by using a splicing tape(10) comprising a carrier layer (13) having on a first major surface afirst adhesive layer (12) and on a second major surface opposite to thefirst major surface in the order given an adhesion-controlling layer(17), a non-tacky polymer layer (14) and a second adhesive layer (15),the splicing tape being capable of delamination between the carrierlayer (13) and the adhesion-controlling layer (17) or between thenon-tacky polymer layer (14) and the adhesion-controlling layer (17),respectively, when preparing the splice.
 8. Splicing tape (10) suitablefor splicing a leading edge portion (34) of the outer turn (32) of aroll of sheet material (30) to another sheet material, said splicingtape comprising a carrier layer (13) having on a first major surface afirst adhesive layer (12) and on a second major surface opposite to thefirst major surface in the order given an adhesion-controlling layer(17), a non-tacky polymer layer (14) and a second adhesive layer (15),the splicing tape being capable of delamination between the carrierlayer (13) and the adhesion-controlling layer (17) or between thenon-tacky polymer layer (14) and the adhesion-controlling layer (17),respectively, when preparing the splice.
 9. Splicing tape (10) accordingto claim 8 wherein the adhesion-controlling layer (17) and the non-tackypolymer layer (14) are selected so that the splicing tape (10) iscapable of delamination between such layers when preparing the splice.10. Splicing tape (10) according to claim 9 wherein the force fnecessary to peel the non-tacky polymer layer (14) from theadhesion-controlling layer (17) is between 10 and 25 g/cm.
 11. Splicingtape (10) according to claim 8 wherein the adhesion-controlling layer(17) of the splicing tape (10) comprises a polysiloxane or fluorinatedpolymer.
 12. Splicing tape (10) according to claim 8 wherein thenon-tacky polymer layer (14) comprises a polymer selected from the groupconsisting of polyvinyl alcohols, polyvinyl chlorides and copolymers ofvinyl acetate and vinyl chloride.
 13. Splicing tape (10) according toclaim 8 wherein the carrier film layer (13) comprises paper.